Synchronizing device



L. F. KENNEDY SYNCHRONIZING DEVICE Aug. 14, 1928. 1,680,739

Original Filed May 1926 Inventor: Luke F Kennedy, by Mfg M His AGtOTTWGg.

Patented Aug 14,1928.

A 1 1, 80,739 omen STAT S A E FI f V LUKE F. KENNEDY, OF SGHENECTADY, YORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF YORK.

syncn-nomzme DEVICE.-

npplication filed flayi, 1926, Serial No. 106,995. 'Renewcdhpril 21, 1928;

phase diflerence between the circuit voltanother.

ages is brought within certain limits and tocause energization of the circuit breaker control circuit at an instant of time sufliciently in advance of phase coincidence between the circuit voltages to-cause the circuit breaker to be closed just as the system voltages are brought into phase with one The time interval between energization of the circuit breakers control circuit and closure. of the switch is substantially constant for any given circuit breaker. The

rapidity with which the circuit voltages. come into synchronism, however, is dependent on the diiference between the system frequencies. In order to ensure closure 0 the circuit breaker' at the instant when the system voltages are in,phase, I provide a synchronizing mechanism which has no moving electrical contacts and operates in accordance with the difference between the system frequencies to cause energization of the switch operating coil at a true prior to phase) coincidence which is. 3 st long enough to ensure closure of the circuit breaker when the phases of the circuit coincide. 1

My invention will be. better understood from the following description when considered'in connection with the accompanying drawing and its scope will be pointed out in the appended claims. e

The drawing illustrates a synchronizing system wherein my invention hasbeen emto be interconnected-through a switch 3 pro vided with an operating coil 4 arranged to be supplied with current from a source 5 through a relay switch 6. Operation of the switch 6 is controlled by ,an operating coil.

7 which is connected to a current supply circuit 8 through a light responsive means shown as a photo-electric cell'9. Light for controlling the operation of the cell 9 is supplied from a source 10 through perforat1ons or openings 11 and 12 located near the periphery of rotatable disks 13 and 14 wh1ch form a part of a synchronizing mechanism 15.

The disk 14 is fixed to'a rotatable shaft 16 and is resiliently coupled through a member 17, a spring 18, and a member 19 to a disk 20 which is free to rotate about the shaft 16 in response to extension or con- .traction of the coupling formed by'the members 17 and 19 and spring, 18. 9A drag magnet 21 is provided for exerting onthe disk 20 aretarding force having its magni tude determined by the rotational speed of the disk. The-disk 20 is coupled to the disk 13-through a gear 22 fixed to the disk 18, a gear 23 mounted to rotate about a shaft 25 fixed to the disk 20 and a contact member 26 fixed tothe end of the member 25 and arranged to cooperate with a member arrangement, the disk 14 rotates with the 24 whichis fixed to the disk 14, a member i 27 which is fixed to the gear 23. -with this response to relative motion between. the

disks 14 and 20 produced by extension or contraction of the resilient coupling between the disks 14 and 20.

Rotation of the shaft 16 maybe eifected by any suitable device that is responsive to the phase and frequency relations existing between the electromotiv'e forces of the circuits 1 and 2. This device has been shown as comprising afistator winding28 connected to the circuit 1 through a transformer 29 and a rotor winding 30 mounted on the shaft .16 and connected to the circuit 2 through a' transformer 31. It will be apparent, however, that synchronous motors mechanically interconnected through a difv 'ferential gear similar to that illustrated in Letters Patent of J. L. Hall, No. 706,554,

or other suitable means may be substituted for the windings 28 and"30. In any case the angular position of the disk 20 about the shaft .16 will determine the angular position of the opening 11 about this shaft. The operation of the synchronizing device 15 will be readily understood if it be' as- "s'umed that the switch 3 is open and the differ but slightly, the rotational speed of stator winding 28 has been adjusted about the shaft 16 is comparatively slow, the flexi- Car 'flexible or resilient coupling between the speed of the shaft 16 is higher, a greater the shaft ,16. to aline the light source and ble coupling between disks 14 and tends the opening 11 with'the middle of the-slot to contract, the opening 11 is angularly ad- 12 when the systems" are in phase and the vanced about the shaft 16 and the switch spring 18 is contracted. If the circuits '1. operating coil is energized at an instant of and 2 are operating at widely different fretime which precedes phase coincidence of quencies, the speeds of the rotating fields the circuit voltages by an interval of time produced through windings 28, and are just long enough to ensure closure of the widely different, the-shaft 16 is rotated at a switch at the instant when the voltages come 75 comparativelyhigh rate ofspee'd, a cominto phase with oneanother. Ifthe differ-e paratively large retarding 1 force is exerted ence between the frequencies of the voltages on the disk 20 by the drag magnet21, the becomes greater, however, the rotational disks-14 and 20 is extended, the perforation tensile force is exerted on the spring 18 by 11 is maintained out of alinement with the the drag magnet, the angular advance of light source 10, slot 12 and the photo-electric the opening 11 about the shaft 16 is decell 9 and the connection between the curcreased in roportion to the increase in frerent supply means 8 and operating coil? is quency di erence, and the switch operating interrupted. coil is still ener ized' at an instant of time .35 Asthe frequencies of the circuits 1 and 2 which precedes p ase coincidence of the sysapproach equality, the rotational speed of -tem voltages by a time interval permitting "the shaft 16 decreases, a smaller retarding. closure of the switch at the proper instant.

' force is exerted on-the disk 20 by the drag The synchronizing device 15 thus operates switch 3 is produced.

magnet 21, and the flexible coupling between over a range of frequenc difference deterthe disks 14 and 20 contracts and tends 'to mined by the length of t e slot 12 to cause rotate the disks 13 and 20 in opposite direcenergization of the switch operating coil suftions about the shaft 16 so that the opening ficiently in advance of phase coincidence be- 11 is alined with the light source 10, slot 12 tween the circuit voltages to produce interand the cell 9 each time the system voltages connection of the circuits just as they come come into phase with one another. When into phase with one another.

the system frequencies are sufliciently near The embodiment of the invention illusequality to permit closure of the switch 3, trated and described hereinhas been selectedthe opening 11 comes into alinement with for the purpose of clearly setting forth the -the light source 10- and cell 9-at an instant principles involved. It will be apparent,

of time preceding phase coincidence between however, that the invention is susceptible of the circuit voltages by a timeinterv'al deterbeing modified e t h diff re o imined .b the actual difference between the tion's encountered in its. use, and I therefore system requencies. When this occurs, curaim to cover by the appended'claims all rent is transmitted through the photo-elecmodifications within the true spirit and tric cell 9; the operating coils 7 and 4 are scope of my invention. successively energized and closure of .the a What I claim as newand desire to secure by Letters Patent of the United States, is

As previously stated, the stator winding 1. The combination of a plurality of alter- 28 is so adjusted about the shaft 16 as to natingcurrent circuits, means for interconcause the'opening 11 to be in alinement with necting said circuits, and means comprising the light source 10 and the cell 9 or center a light responsive device forcausin'g said of the slot 12 when the systems are in phase interconnecting means to be energized at an i and the spring 18 is contracted. The anguinstant of time preceding phase coincidence lar position of the opening 11 about the in the voltages of said circuits by a time inshaft 16, however, is dependent on the shaft terval whic q is substantially constant over speed and consequently on the difierence'bea predetermined rangein the difference between the circuit frequencies. This angula tween the frequencies of said circuits.

adjustment of the opening 11 relative tolthe 2. A synchronizing devicev com rising a cell 9 in accordance with the difference be-' rotatable. shaft, a perforated mem x tween the circuit: frequencies is essential be to said shaft, a member rotatable about said cause the time intervalbetween energizationshaft and con led to said fixed member of-the sw1tch o eratin coil and closure of throug a lesllient p i g, and 11 P the switch is sustantia ly constant, whereas forated member rotatable abo S Shaft the time required for the opening 11 to move in response to relative movement between I through any given an 1e into alinement with said coupled members, the arrangement light source 10 and t e cell 9 is dependent. being such that the perforations of said quencies.

on' the difference between the system freperforated members are alined when said I coupling is contracted. Thus, 1f the frequencies ofthetwo 3. A. synchronizing device comprising a rotatable shaft, a perforated member'fixed to said shaft, a member rotatable about said shaft and coupled to saidfixed' member through a resilient'coupling, a perforatedv member rotatable about said shaft in re-. sponse to relative movement between said coupled members, and a light responsive device arranged to be alined with the perforations of said perforated members when said coupling is contracted.

4. A synchronizing device comprising a rotatable shaft, a perforated member fixed to said shaft, a member rotatable about said shaft and coupled to said fixed member through a resilient coupling, a perforated member rotatable about said shaft incresponse to relative movement between said coupled members, a source of light, and a light responsive device arranged to be alined with said source and the perforations of said perforated members when said coupling is I contracted.

5. The combination of a rotatable shaft, a

perforated member rotatable about said;

shaft and coupled to said fixed member through a resilient coupling, means for ex- ,erting on said rotatable member a retarding force which is dependent on the rotational speed of said shaft, and a perforated member rotatable about said shaft in response to relative movement produced between said coupled members by saidret'arding force,

the arrangement being such that the perforations of said perforated members are alined when said retarding force is zero.

6. The combination of a plurality of electrical circuits, a rotatable shaft, means for rotating said shaft at a speed, proportional to the difference between the frequencies of said circuits, a perforated member fixedto said shaft, a member rotatable about saidshaft and coupled to said fixed member through a resilient coupling, and aperforated member rotatable about said shaft in response to relative movement between said coupled members, the arrangement being such that the perforations of said perforated members are alined when the" frequencies of said circuits are substantially Cal a speed of the rotatable member whereby'to cause movement of the disk relatively to the member.

.8. Sychronizingwapparatus comprising a L rotatable member adapted to be actuated at aspeed dependent on the difference between the frequencies of two electromotive forces and having a light passing means, a movable member. having a light passing ineans,

a source of light and means for causing relative movement of said members whereby I to aline said light passing means and said light source comprising a disk coupled to said rotatable member and means for retarding the movement of the disk in accordancewith the speed of the rotatable member whereby to cause movement of the disk relativelyto the rotatable member.

9. Synchronizingapparatus comprising a Y rotatable member adapted to be actuated at 'a speed dependent on the difference between tive movement of said members whereby to aline said light passing means and said light source comprising a rotatable .disk, a flexible coupling between the disk and the rotatable j member and means for retarding the movement of the disk in accordance with t J speed of the rotatable member whereby to cause movement of the disk relatively to the rotatable member.

10. Synchronizing apparatus comprising a rotatable member having a light passing means and adapted to be actuated at a speed dependent on the difference between the frequencies of two electromotive forces, a movable member having a light passing means, I

a source of light and means for causing relative movement of said members where by to aline said light passing means and said light source comprising a disk, a fiexible coupling between said disk and said rotatable member and means for retarding the movement of the disk in accordance with the speed of the rotatable member whereby to cause movement of the disk relatively to the rotatable member. r i a 11. Synchronizing apparatus comprising a rotatable member having alight passing means and adapted to be actuated at a speed dependent on the difference between .the frequencies of two electromotive forces, a movable member having, a light passing means, a source of light on one side of one of said members, a light responsive device on the opposite side of the other member and means for causing relative movement of said mem-.

here in accordance with the speed of said rotatable member whereby to aline said light passing means with the light source and the light responsive means when the speed is less than a predetermined value. 7

12. Synchronizing apparatus comprising a rotatable member having a light passing means and adapted to be actuated at a. speed members, a hght responsive device on the opposite side of the other member and means .for causing relative 'movement of said mem- 10ers in accordance with the s eed of said rotatable member whereby to allne said light 10' passing means with the light source and the light responsive means when the speed is less than a predetermined value, and circuit controlling means arranged to be controlled by said light responsive means when said light passing means, said source and said light responslve means are m, alinement.

In witness whereof I have hereunto set my ,hand this 4th day'of'May, 1926.

LUKE F. KENN DY. 

